"And God said, Let the waters bring forth
abundantly the moving creature that hath life, and fowl that may
fly above the earth in the open firmament of heaven." Genesis
1:20.
God's creation of life in the waters normally
brings to mind the fish, frogs, jellyfish, and other common water
animals. But, within aquatic environments of the earth is an animal
that most people will never see and have never heard of - the
Bear of the Moss or Water Bear. This little-heard-of creature
is among some of the amazing animals in God's creation.
The phylum Tardigrade has almost one thousand
little-known and mostly microscopic organisms in it. These animals
are invertebrates. The largest are just barely visible to the
naked eye being about the size of the dot made by a fine lead
pencil. They look like miniature caterpillars and have five body
segments and four pairs of clawed legs. They have many organ systems
like larger animals but lack respiratory and circulatory systems.
They breathe through their skin, and their whole bodies work to
pump fluids throughout their bodies.
The word tardigrade means "slow walker,"
which is a good description of their movements. They have sluggish,
clumsy movements as they crawl around on the bottom sediment of
their water home, living in decomposing materials on the bottom
of bodies of both salt and freshwater, on water trapped in mosses
and lichens, and even in deserts under special conditions. They
must have water to find food, breathe, and to reproduce but are
able to survive for long times when water is not available. This
ability to survive extreme environmental swings is of special
interest to scientists today.
When conditions of low oxygen supply occur in
the water, tardigrades have been given a neat "trick"
by God called anoxybiosis. Most normal people have never
heard of anoxybiosis which is, indeed, an amazing ability. When
flooding occurs for bears of the moss and oxygen levels drop below
tolerable levels, the tardigrades swell up like little balloons.
This inflating allows them to float around at the top of the levels
of water where more oxygen will be available by diffusion with
the air. They can float around like this for several days as they
wait for the water levels to drop back down to normal levels and
they find another home among the mosses and lichens or at the
bottom of the stream. They then shrink back down to normal and
feed growing and reproducing. God has given the tardigrades this
amazing survival feature, but that is not the only condition they
can survive.
They also exhibit "cryptobiosis." Cryptobiosis
occurs when the environment conditions are just the opposite of
too much water when it is too dry. If the stream, pond, puddle,
moss, lichen, or other home for the tardigrades dries up, then
the tardigrades can go into a "reversible state of metabolic
suspension," which is sort of a suspended animation. They
dry up and shrivel into a wrinkled shape called a "tun,"
which is about one-third their former sizes. In cryptobiosis,
they can survive for long periods of time without food or water.
They can enter this condition and return to normal in a matter
of just a few hours. Tardigrades have shown that they can survive
very cold conditions down to -272.95C for up to twenty hours.
They have survived at 120C at 1000 atmospheres and in high vacuums.
In this cryptobiotic state, they have shown resistance to hydrogen
sulfide, ultraviolet light, and even X-rays. One could think that
these organisms could travel unprotected through space without
any ill effects. Some tardigrades have been kept alive for more
than 100 years by going in and out of this condition.
The "bears of the moss" or "water
bears" are among the most unknown of God's creatures and,
yet, have some of the most unusual features of any animal on the
planet earth. Let us marvel and praise the Creator for the microscopic
things we have never seen in the world around us. Rt. 1 Box 116A,
Belington, WV 26250. aedeverson@yahoo.com